Screw plug and method of making same



T. L. RYERSON.

SCREW PLUG AND METHOD OF MAKING SAME P L CATIO 4 919 L419,58 Patented June 13, 1922.

, UNHTEEDD stars PATENT @FHC.

THORVAL L. RYERSON, OF PARK RIDGE, ILLINOIS, ASSIGNOR TO W. D. ALLEN MANU- FACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION.

SCREW PLUG AND METHOD OF MAKING SAME.

Application filed. August 4, 1919.

T0 all whom it may concern:

' Be it known that I, THORVAL L. RYERsoN, a citizen of the United States, residing at Park Ridge, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Screw Plugs and scribed, illustrated in the accompanying drawing and particularly pointed out in the claims at the end of this specification.

In the manufacture of screw plugs of the type to which my invention more particularly relates, i. e., screw plugs such as are largely used in and about automobiles, it has heretofore been the practice to form such plugs of cast metal with squared heads and with tapering bodies having screw threads cut thereon. This method of making screw plugs is objectionable for several reasons, notably because of the inaccuracy in casting the plugs with the squared heads exact-1y centered with respect to the end of the plug and because, also, of the expense incident to cutting threads upon the'bodies of the plugs. My present invention provides a screw plug formed preferably of soft steel having a tapered body portion and with a square or polygonal head, the body and head of the plug being brought to proper shape by means of suitable dies and the threads being subsequently rolled upon the tapered bod r r R eferring to the accompanying drawing, Figure 1 represents a piece of steel rod cut to proper length to form my improved screw plug. Figure 2 shows the plug after it has been subjected to the action of suitable dies for effecting the tapering of the body of the plug and the formation of its squared end.

igure 3 shows the plug after the sprue or fin resulting from the forging dies has been removed. Figure 4 shows the finished plug after .the screw threads have been rolled Specification of Letters Patent. Patgnfljedl June, 13, 1922,

Serial No. 315,356.

thereon. Figure 5 is atop plan View ofthe plug. v

In making my improved plug, a steel rod of suitable size will be cut into proper lengths to form blanks corresponding to the length of the plug to be formed. This blank or section of steel rod shown in Figure 1 of the drawings is placed between suitable opposing dies, one of which serves to form (see Figs. 2 and '5) and to remove this fin 0 the blankwill be forced through another die the interior diameter of which corresponds to the diameter of the tapered body a at its largest point. When the blank passes through the last mentioned die it will be left in the condition shown in Fig. 3 of the drawing, after which the blank will be subjected to suitable dies whereby the threads (i will be rolled upon the tapered body portion of the blank.

The screw plug embodying vmy invention can be formed not only more cheaply than the cast metal screw plugs hereinbefore mentioned, but my improved plug has the j further-advantage that the square or polygonal head of the plug is always accurately centered so that it can be much more easily and effectively turned by the wrench used in seating and unseating the plug.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. A screw plug having a tapered and threaded body portion and a square head, said plug being initially shaped between a set of forging dies, and the threads rolled on the body portion of the shaped plug between threading dies.

2. The method of making a screw plug having a tapered body portion and a polygonal head consisting in shaping the plug between a set of forging dies, and rolling the threads on the body portion of the shaped plug between threading dies.

3. The method of making a screw plug having a tapered body portion and a square shaping the plug between a set of forging dies, submitting the shaped blank to trimming dies to remove the flash or fin, and 10 rolling the threads on the body portion of the shaped plug between threading dies.

THORVAL L. RYERSON. 

